Crosslinked polyurea from dihydrazides of methylated muconic acids

ABSTRACT

Novel linear polymers having high melting points and suitable for use as adhesives, sealants, films, surface coatings and as chromotographic agents can be prepared from dihydrazides of methylated muconic acids either singularly or in mixtures with each other and an organic diisocyanate. The linear polymer may also be crosslinked by heat or free radicals or with ethylenically unsaturated monomers to produce useful films and coatings.

United States Patent [1 1 Cassar CROSSLINKED POLYUREA FROM DIHYDRAZIDES OF METHYLATED MUCONIC ACIDS [75] Inventor: Richard D. Cassar, West Chester,

[73] Assignee: Sun Research and Development Co.,

Philadelphia, Pa.

[22] Filed: Dec. 30, 1971 [21] Appl. No.: 214,402

[52] US. Cl 260/859 R, 260/775 CH [51] Int. Cl C08g 41/04 [58] Field of Search 260/859, 77.5 CH

[56] References Cited UNITED STATES PATENTS 3,004,945 10/1961 Farago 260/775 CH FOREIGN PATENTS OR APPLICATIONS 9/1966 Great Britain 260/775 51 Sept. 11, 1973 OTHER PUBLlCATlONS Milas, Nicholas A. et al., Chemical Abstracts, volume 51, 2596b 1957. I

Primary Examincr Paul Lieberman Attorney-George L. Church/Donald R, Johnson et al.

571 ABSTRACT 4 Claims, No Drawings CROSSLINKED POLYUREA FROM DIIIYDRAZIDES OF METHYLATED MUCONIC ACIDS BACKGROUND OF THE INVENTION there is a constant endeavor in the field of polymer chemistry to obtain synthetic polymeric material having outstanding chemical and physical properties. It has been found that recently discovered derivatives of methylated muconic acid specifically disclosed in commonly assigned application Ser. No. 49,116, of Anne R. Donnell when polymerized with organic diisocyanates produce a polymer having superior qualities.

SUMMARY OF THE INVENTION A new group of synthetic polymer compositions having outstanding chemical and mechanical properties which can retain these properties by withstanding the degradative effects of heat, oxidation and ultraviolet light has now been discovered. These polymers have utility as adhesives, sealants, films, surface coatings and as chromatographic agents.

Briefly stated the instant invention comprises polymers havingthe general formula: c

wherein Y is adivalent radical selected from the group consisting ofz- T t plished with the aid ofan antisolvent. Methanol is usuand -CH, with at least one 1R being CH,. Z is an organic divalent radical selected from the group consisting of alky'lene, arylene, icycloalkylene,

' where I a 1) (relative) t/Io alkarylene and aralkylene and n is the number of repeating units. 1

DESCRIPTION OF THE PREFERRED EMBODIMENTS The novel polymers of this invention areprepared by polymerizing the dihydrazides of methylated muconic acids (and mixtures thereof with each other) with an organic diisocyanate. The present polymers are particularly interesting since they provide an abundance of functional groups e.g., amide and carboxy which may serve as reactive sites on the polymer chain in addition to having unsaturated positions available for crosslink- Generally, a stoichiometric ratio of dihydrazide component to organic diisocyanate component is employed although it is sometimes desirable to use a slight excess of thediisocyanate. A slight excess could be used if the diisocyanate were not of high purity since it picks up water and hydrolyzes easily.

A solution polymerization is preferably employed to produce the polymer of the invention. Suitable solvents for polymerization include dimethylsulfoxide, hexamethylphosphoramide, N,N-dimethylformaide and mcresol. Most preferably, however, dimethylsulfoxide is used. I 2

Reaction conditions of temperature and pressure may vary over a wide range. For example, operable temperaturesrange between 72C..and 250C. and preferably between 20C. and 50C. Similarly the pressure may rangefrom subatmospheric 0.01 atmosphere to superatmospheric 10 atmospheres but preferably from l atmosphere to 3 atmospheres. The reaction is conducted in a closed vessel with a nitrogen'blanket to insure a moisture-free atmosphere.-

' Sometimes the polymer product will not be dissolved by the solventsemployed in the polymerizations in any substantial amountsSuch a system results in a precipitation-of the polymer which can be easily recovered fromthe reaction of the polymer which can be easily recoveredfrom the reaction mixtureby conventional means. It is however, entirely permissible to use a solvent in which thep'olymerproduct is soluble since the film or fiber could be produced directly therefrom. Re-

covery of the polymerfrom solution is usually accom- The polymers of the present inventionhave inherent viscosities in the range of 0.50 to 2.0. This corresponds to n is equal to 5 -l00.1The prefera'blerange is n is equal to 50-7 5. Tl'ie inherentv viscosity .is indicative of the degree of polymerization and is used herein as a measure thereof. Inherent viscosity is represented by the equation Y to flow time through'a viscometer of a liquid reference ft flow time through the same viscometer of a ,dilute solution of polymerginithe reference liquid.

. :.c concentration of polymer .in solution expressed wherein R,, R,, R, and R ar elected from .hydrogen 5 grams/deciliter.

' such as styrene case indesired .form,; then cured. The

linear polymers of the invention can also be crosslinked with themselves without any additional crosslinking agent. Suitable crosslinking agents include styrene, butadiene, methyl methacrylate, vinylacetate, acrylonitrile, vinylidene chloride, isoprene, and the like. Either conventional hot or cold curing procedures can be used.

The curable polymers as described above are dissolved in the crosslinking agent by heating to a temperature in the range of 40 to 100C. The blending can take place in the presence of a small amount of a polymerization inhibitor such as hydroquinone or 2,6-di-tbutylphenol to prevent premature crosslinking.

In handling the curable polymers of the invention as in the production of films, fiber, cord, molded articles or blends with crosslinking agents the temperature of the polymers should be kept below 220C. At 220C. the curable polymer will begin crosslinking with itself by a free radial mechanism. Up to 15 moles of crosslinking agent per mole of unsaturation can be employed, preferably a mole ratio in the range of 1:5 to 5:1 is employed.

After blending, the mixture can be hot cured at a temperature in the range of 50 to 150C. for 0.5 to hours or cold cured at a temperature of to 50C for 0.5 to 10 hours.

,A free radical catalyst is preferably employed in the curing thus allowing lower curing temperatures. Suitable catalysts include the peroxides such as benzoyl peroxide or azo-bis-isobutyronitrile for hot cures and methyl ethyl ketone peroxide in dimethyl phthalate and 1 percent cobalt naphthenate in a styrene for cold cures. Hot cures can be conducted at a temperature in the range of 50-l50C. for 0.5 to 10 hours and cold cures at a temperature of 20 to 50C. for 0.5 to l0 hours.

In addition to catalysts, promoters or accelerators such as N,N-dimethylaniline can be employed during curing. Prior to curing fillerssuch as glass wool and asbestos, carbon, color pigments and the like can be added.

The following illustration is typical of the reactions in the examples and should serve as a guide to the polymers obtained in each to those within the scope of the invention generally. The reaction in the illustration involves a, a-dimethyl-trans, trans-muconyl dihydrazide and 1,6-diisocyana-tohexane (hexamethylene diisocyaner product in the final re- .-.|ined from X-ray diffraction ectroscopy data.

7 49,176, filed June 23, 1970, by admixing a solution of the methylated muconic acid with a stoichiometric quantity of hydrazine and recovering crystals of the dihydrazide product. This reaction can be effected at a temperature range of 5 to C. with a temperature range of 20 to 35C. being preferred. The rate of reaction is partially dependent upon the solubility of the reactants in the liquid reaction medium used. The crystalline dihydrazide can be recovered by filtering or any of the other well-known standard procedures used for recovering solids from liquids. The dihydrazides of methylated muconic acids can be prepared from any isomers of the acid or from the mono or diesters of the acids, preparation from the ester being preferred. Some of the diacids and their ester forming derivatives are disclosed in Ser.No. 49,176 and the disclosures of patents mentioned therein are intended to be incorporated here by reference. Exemplary of some of the methylated muconic acids suitable for use in the preparation of the dihydrazides include oz-methylmuconicv acid, B methylmuconic acid, a, a-dimethylmuconic acid,.a, B-dimethylmuconic acid, a, a, B-trimethylmuconic acid, a, B, B-trimethylmuconic acid, a, a, B, B-tetramethylmuconic acid and/or monoesters of each of the abovenamed methylated muconic acids wherein one carboxyl group is attached to a C, to C hydrocarbyl radical or their diesters wherein each carboxyl group is attached to a C, to C hydrocarbyl radical and mixtures thereof. Each of the above disclosed methylated muconic acids in the cis-cis, cis-trans or trans-trans isomeric form or mixtures thereof is effective for use in the preparation of the dihydrazides.

The hydrocarbyl esters of methylated muconic acids containing C, to C carbon atoms are also suitable for use in preparing the dihydrazide compositions useful in the present invention areselected from the hydrocarbyl lLln radicals of C, to C hydrocarbonshaving acyclic, cyclic and aromatic structures such as those disclosed in the text HANDBOOK OF HYDROCARBONNS, S. W.

'isocyanate; 4,4'-biphenylene Ferris, Academic Press lnc.,N.Y. (1955), pages 145 to 249 all of which are incorporated therein by reference. Preferred esters suitable for use in preparing the dihydrazide compositions suitable for use in the present invention include the C, to C hydrocarbyl mono and diesters of the methylated muconic acids hereinabove disclosed. Examples of C, to C hydrocarbyl groups include methyl, ethyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, cyclopentyl, methylcyclopentyl, dicyclopentyl, cyclohexyl, phenyl, tolyl, xylyl, naphthyl, tetrahydronaphthyl, as well as various isomers of each and mixtures of all.

Examples of some of the esters of the polymethylated muconic acids suitable for use in preparation of the dihydrazide compositions of the present invention include mono and dimethyl esters of a-methylmuconic acid, the mono and dimethyl esters of B-methylmuconic acid, the mono and dimethyl esters of a, a-dimethylmuconic acid, the mono and dimethyl esters of a, B'-dimethylmuconic acid, the mono and diphenyl esters of a, 60-B,B' fetramethyimuconic acidfthe mono and dinaphthyl esters pf a, B, B'-trimethylmuconic acid, the mone and di-5,6-diethylacenaphthyl esters of a, a'-dimethylmuconic acid, the mono and dicyclohexyl ester of a, a-dimethylmuconic acid, the mone and di-l,Z-dimethylcycloheptyl esters of a, B-di methylmuconic acid, the mono and didecahydronaphthyl esters of a, a B, B'-tetramethylmuconic acid, the mono and di-l ,3-dipropylbenzyl esters of a, a'-dimethylmuconic acid, the mono and di-2,9-dimethyl-4,7- diisobutyldecyl esters of a, a, B B-trimethylmuconic acid, the mone and dianthracyl esters of a, B'-dimethylmuconic acid, mono and di-2,6,l0-trimethyl decyl esters of a, a'B, B, tetramethylmuconic acid and the nonyl ethyl esters of a, a B, B, -tetramethylmuconic acid.

For purposes of general definition, the methylated muconic acid dihydrazide composition useful in the present invention can be defined by the following structural formula: I

The preferred compositions of the present invention are polymethylated muconic acid dihydrazides. Referring to the structural formula, the dihyrazides of polymethyled muconic acid wherein R and Rfare methyl groups R; and R, are hydrogen radicals is normally referred to as the dihydrazides of a, a-dimethyl-cis-cis, cis-trans, trans-trans, preferred muconic acid.

The organic diisocyanates used in the invention are any conventional diisocyanates capable of entering into addition polymerization reactons. The diisocyanates have the formula O=C=NZ--N=C=O wherein Z isa divalent organic radical selected from the class consisting of alkylene, arylene, cycloalkylene, alkarylene and arlkyene. Exemplary of such diisocyanates are aliphatic diisocyanates of the formula O='C=N-(CH,. ),,N=C=O where n is an integer from 2 to about O-xylylenediisocyanate, l,4-diisocyanatocyclohexane; 1,3-diisocyanatobenzene; bis(p-iso-cyanatohexyl) methane; 1,6-diisocyanatohexane (hexamethylene diisocyanate'); toluene-2,4-diisocyanate; p-phenylene didiisocyanate; p,p'-

from hydrogen isopropylidene diphenyl diisocyanate, 4,methyl-rphenyl diisocyanate; methylene bis (4- phenylisocyanate); 4-chloro-l,3-phenylene diisocyanate; l,5-naphthylene diisocyanate; and l,S-tetrahydronaphthalene diisocyanate. Arylene diisocyanates, i,e., those in which each of the diisocyanate groups is attached directly to an aromatic ring, are preferred to complement the polycyclic diisocyanates.

The examples presented herein are intended to be merely illustrative and are not intended to limit the scope of the claims. Certain ratios of reactants have been specified. It is to be understood that those of skill in the art will be able to select the respective proportion from each range so as to produce compositions within the spirit and scope of the invention as disclosed. The examples provide guidelines to incidate to those of skill in the art the means and manner of reactant selection, procedures for utilizing the reactants, and the gem eral nature of the polymides to be obtained.

EXAMPLE I A mixture of 50 ml. dried dimethylsulfoxide and 3.96 grams of a, a-dimethyl-trans,trans-muconic acid dihydrazide is stirred in a closed reaction vessel under a nitrogen blanket. The dimethylsulfoxide is dried by distillation at reduced pressure. When the dihydrazide has become saturated, 3,48 grams toluene-2,4-diisocyanate is added. As the diisocyanate dissolves, the reaction proceeds exothermically with the evolution of carbon dioxide. After the gas evolution has practically ceased, the reaction is warmed to 60C. and stirred for 2 additional hours. The resulting solution is viscous, clear and pale yellow. Clear tough films may be cast directly and dried in a vacuum oven at 60-80C. The polymer may also be isolated from the original solution by precipitation in water, followed by thorough washing with water in a Waring blender. After filtering and drying in a vacuum 'oven at 60-80C., the inherent viscosity in dimethylsulfoxide is about 0.11 (0.5 percent conc., 25C). The polymer melt temperature is l9l-l92.5C.

I claim:

. I. A crosslinked polymer comprising:

a. a linear polymer having the'following structural formula:

wherein Y is a divalent radical of the group consisting of mer to unsaturation of from 1:5 to 5:1.

3. A crosslinked polymer according to claim 1 wherein the monomer is selected from the group consisting of styrene, butadiene, methyl. methacrylate, vinyl acetate, acrylonitrile, vinylidene-chloride bisoprenc.

4. A crosslinked polymer according to claim 3 wherein the monomer has a mole vratio or monomer to unsaturation of from 1:5 to 5:1.

* III t 

2. A crosslinked polymer according to claim 1 wherein the vinyl monomer has a mole ratio of monomer to unsaturation of from 1:5 to 5:1.
 3. A crosslinked polymer according to claim 1 wherein the monomer is selected from the group consisting of styrene, butadiene, methyl methacrylate, vinyl acetate, acrylonitrile, vinylidene chloride bisoprene.
 4. A crosslinked polymer according to claim 3 wherein the monomer has a mole ratio or monomer to unsaturation of from 1:5 to 5:1. 